1. Field of the Invention
The present invention relates to a draw processing device, a drawing method, a draw program, and a computer-readable recording medium having recorded therein the draw program, all of which are aimed at drawing images on a two-dimensional screen of devices such as television monitor device.
2. Description of the Related Art
There are accelerated trends in higher integration and faster processing speed of processors and memories in recent television game consoles and personal computers, so that draw processing devices such as television game consoles and personal computers can generate three-dimensional images full of real presence, reality and perspective representation in a real-time manner, and can display them on a two-dimensional screen.
Another recent trend relates to a process in which the individual polygons composing a three-dimensional image to be drawn on a two-dimensional screen are subjected to rendering in a plurality of paths to thereby paste a plurality of textures (referred to as multi-path rendering hereinafter), which is advantageous for raising reality of the three-dimensional image drawn on the two-dimensional screen.
In a conventional draw processing device, a main processor of the device serially produces geometry data which comprises polygon apex coordinate data, texture coordinate data and brightness data, and then sends them to a graphic processor for executing draw processing using the geometry data. Therefore the main processor has to generate the geometry data containing the same apex coordinate data every time the individual rendering paths are executed, and has to serially send thus generated geometry data to the graphic processor. This was causative of an excessive load for the main processor of the conventional draw processing device in multi-path rendering.
For the case the multi-path rendering is executed for a plurality of polygons, the volume of geometry data transferred from the main processor to the graphic processor will be vast in proportion to both the number of polygons and the number of rendering paths, so that a large percentage of the band width of a bus wiring which connects the main processor and graphic processor is undesirably occupied only for the transfer of the geometry data, which considerably lowers the speed of data transfer from the main processor to graphic processor.
The same problem may also occur when a plurality of polygons having the same shape are subjected to rendering, or when a plurality of polygon planes having different texture blending ratios are synthesized, which process is generally referred to as multi-texture drawing.
More specifically, for the case that a plurality of polygons having an identical shape are to be drawn using an ordinary draw processing device, the main processor must generate geometry data for every polygon and must transfer thus generated geometry data to the graphic processor, which results in the same problem as described in the above.
As for multi-texture drawing, the main processor must generate geometry data together with base-point values and blending ratios for a plurality of textures used for the blend drawing onto the polygon planes for every polygon plane differing in the texture blending ratio, and must serially transfer thus generated data to the graphic processor, which again results in the same problem as described in the above.